Aerial imagery from the UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01

This portion of the data release presents the raw aerial imagery collected during the unoccupied aerial system (UAS) survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01. The imagery was acquired using a Department of Interior-owned 3DR Solo quadcopter fitted with a Ricoh GR II digital camera featuring a global shutter. The camera was mounted using a fixed mount on the bottom of the UAS and oriented in an approximately nadir orientation. A total of six flights were conducted for the survey between 19:35 and 22:15 UTC (12:35 and 15:15 PDT). Only the imagery from fights F03 and F06 were used for data processing and are included in this data release. All flights were conducted at an approximate altitude of 100 meters above ground level resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. Before each flight, the camera's digital ISO, aperture, and shutter speed were adjusted for ambient light conditions. For all flights the camera was triggered at 1 Hz using a built-in intervalometer. After acquisition, the images were renamed to include flight number and acquisition time in the file name. The coordinates of the approximate image acquisition locations were added ('geotagged') to the image metadata (EXIF) using the telemetry log from the UAS onboard single-frequency autonomous GPS. The image EXIF were also updated to include additional information related to the acquisition. The data release includes a total of 1,033 JPG images. Images from takeoff and landing sequences were not used for processing and have been omitted from the data release. To facilitate bulk download, the images from each flight are provided in a zip file named with the flight number. In addition to the provided zip files, the images are also available for browsing and individual download on the USGS Coastal and Marine Hazards and Resources Program Imagery Data System at the following URL: https://cmgds.marine.usgs.gov/idsviewer/data_release/10.5066-P9J9CHOH.

本次发布的数据子集包含2017年11月1日对加利福尼亚州卡梅尔河谷洛斯帕德雷斯水库三角洲开展无人航空系统（Unoccupied Aerial System, UAS）勘测时采集的原始航空影像。本次影像采集使用美国内政部（Department of the Interior）所有的3DR Solo四旋翼无人机，搭载理光GR II（Ricoh GR II）数码相机，该相机配备全局快门（global shutter）。相机通过无人机底部的固定支架安装，整体呈近似天底指向的姿态。本次勘测共开展6次飞行任务，作业时段为协调世界时19:35至22:15（对应太平洋夏令时12:35至15:15）。仅F03与F06两次飞行的影像被用于数据处理，并纳入本次数据发布。所有飞行任务均在距地面约100米的高度开展，标称地面采样距离（ground-sample-distance, GSD）为每像素2.6厘米。每次飞行前，均会根据环境光照条件调整相机的数字感光度（ISO）、光圈与快门速度。所有飞行任务均通过内置间隔计时器以1Hz的频率触发相机拍摄。采集完成后，影像被重命名，文件名包含飞行编号与采集时间。借助无人机搭载的单频自主全球定位系统遥测日志，影像采集位置的近似坐标被添加至影像元数据中，完成地理标记（geotagged）。同时还更新了影像的EXIF元数据（Exchangeable Image File Format），补充与采集相关的额外信息。本次数据发布共包含1033张JPG格式影像。起飞与降落阶段的影像未用于数据处理，因此未纳入本次发布。为便于批量下载，两次飞行的影像分别打包为以飞行编号命名的ZIP压缩文件。除上述压缩文件外，用户还可通过美国地质调查局（United States Geological Survey, USGS）海岸与海洋灾害及资源计划影像数据系统浏览并单独下载影像，访问链接为：https://cmgds.marine.usgs.gov/idsviewer/data_release/10.5066-P9J9CHOH。